Definicija: A system of uniformly spaced perpendicular lines and horizontal lines running north and south, and east and west on a map, chart, or aerial photograph; used in locating points.

Definicija: Sistem enakomerno porazdeljenih navpičnih in vodoravnih črt, ki so pravokotne druga na drugo in na zemljevidih, kartah ali letalskih posnetkih potekajo od severa proti jugu in od vzhoda na zahod; uporabljajo se za določanje točk.

Definicija: An object whose surface contains faces, each of which is described by a simple polygone.